The best of the bests is The 12 apostles of Great Ocean Road(To SW 3 hr from Melbourne)needs whole day to visit. The 2nd is Blue moutain in the west of Sydney,The 3rd is the Rainforests near Cairns, Of course, Sydney and golden coast will be on your list too.
If you have time, Watsons Bay by the ferry near Sydney should not be missed, the fried fish on the dock over there is unforgettable tasty!
Good luck
